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As a smoky haze hangs over Calgary, Environment Canada has issued an alert about air quality, warning the smoke could pose a health threat to people with respiratory conditions such as asthma and heart conditions.

Smoke has been blanketing Calgary for several days as forest fires continue to burn in Alberta and B.C.

Environment Canada says the haze could remain for another 24 to 48 hours.

Alberta Environment forecasts air quality in both Edmonton and Red Deer will rise to level 5 on Thursday and jump to 7 on Friday, which is considered high risk. The air quality index in Calgary was expected to reach 6 on both Thursday and Friday. That is considered moderate.

Smoke and ash in Edmonton, July 16, 2014

Dean Twardzik, Global News

Experts are warning about the health risks.

“Those individuals would be young children, the elderly and people with pre-existing health conditions,” says Kristen Matthews, regional manager with The Lung Association of Alberta. “If you do have children that for example have asthma, it might be best to have them spend the day inside with the doors and windows closed.”

People with conditions like COPD, Angina and heart failures should also seek medical attention if they experience symptoms.

“Anything from shortness of breath to chest tightness to wheezing could be early signs,” says EMS spokesperson, Adam Loria. “As well, if you’re on any prescribed medications, ensure you stay on top of that medication regime.”

Albertans can keep an eye on air quality using a free app from the province. On Thursday, the Alberta Health Quality Index app listed air quality in Calgary at a 4, forecasting a 6 for friday. Between 4 and 6, people considered at risk should limit outdoor activities but anyone with healthy lungs should be fine unless they experience symptoms.